1. Field of the Invention
The present invention relates to an HVAC unit for providing temperature control to a vehicle cabin.
2. Description of the Prior Art
In an automotive vehicle, limited space is allotted beneath or in front of the instrument panel for the heating, ventilation, and air conditioning (HVAC) system. In vehicles having a single zone systems compactly designed to fit within the allotted space, it is sometimes desirable to provide an additional temperature-controlled zone. A system with multiple temperature-controlled zones allows the driver and passenger to have separate controls of the temperature in their respective zone thereby maximizing the comfort of each individual. Extending the zone system even further, i.e., a separate control for the rear seat region, may also be desirable.
Single zone systems are generally designed to optimally utilize the amount of available space in a given type of vehicle as well as to conform to the shape of that space. When a dual zone system is designed, it generally must conform to the same size and shape, thereby requiring additional function to be added without utilizing any extra space. Moreover, when a dual zone system is provided for a particular vehicle line, it is often desired to offer to customers the option of a less expensive single zone system as well. However, the designing and tooling of different systems is sometimes prohibitive for some vehicle models.
HVAC modules produced for use in vehicles typically provide temperature control either to a single zone or to dual zones, i.e., the entire HVAC module is dedicated to one or the other. HVAC modules that have the capability of providing temperature control for an additional zone are specifically designed, tooled and manufactured for the exact number of zones. The numbers or volumes for multiple zone modules are typically much lower than the numbers or volumes for single or dual zone modules. As such, it is much more expensive to design such a multiple zone module for so few vehicles. Additionally, it would be disruptive to the manufacturing cell and the manufacturing process in general to be forced to build an entirely different HVAC module to achieve an additional temperature-controlled zone.
The HVAC units of the prior art provide for multiple, separate streams of temperature-conditioned air being fed to multiple zones. U.S. Pat. No. 6,772,833 B2 to Auer, et al. provides for an HVAC unit including an evaporator, a heater core, a blower, a plurality of blending chambers and an insert mounted within the housing. The insert controls the flow of conditioned air from the blending chambers thus providing multiple separate streams of temperature-conditioned air to multiple zones.
Although the prior art provides for an HVAC unit capable of producing multiple temperature-controlled streams of air to be fed to multiple vehicle zones, a different HVAC unit must be designed and tooled for each discrete number of temperature-controlled streams, i.e., an entirely different HVAC unit for each number of independently temperature-controlled streams for different zones.